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Excavation Material Requirements Estimator

The Excavation Material Requirements Estimator calculates the in-place volume of soil or rock within a simple rectangular excavation and then estimates the loose volume after an entered swell allowance. It can support early haul planning, disposal estimates, trucking discussions, and quantity checks before a more detailed earthwork takeoff is available.

Length, width, and average depth define the bank volume—the volume of material before excavation. The swell allowance represents the increase in volume that can occur after material is disturbed and loosened. Actual excavation geometry may include side slopes, benches, irregular grades, utilities, shoring, or multiple soil types, so those conditions should be measured separately when they materially affect quantity. Swell varies by material and means of excavation; enter a project-appropriate value rather than assuming one fixed percentage.

Excavation dimensions and swell

ft
ft
ft
%
Result
—
bank cubic yards to excavate
Bank volume—
Loose volume after swell—
Swell volume—

1. Enter excavation length
Use the horizontal length of the excavation footprint in feet.

2. Enter excavation width
Use the average or designed width represented by the quantity.

3. Enter average depth
Use a representative vertical depth; split the area into sections if depth varies substantially.

4. Enter swell allowance
Use the expected percentage increase from bank volume to loose excavated volume.

5. Review volumes
The main result shows bank cubic yards; the breakdown also shows loose cubic yards and the added swell volume.

Bank cubic feet = Length × Width × Average depthBank cubic yards = Bank cubic feet ÷ 27Loose cubic yards = Bank cubic yards × (1 + Swell % ÷ 100)

Where:

  • Length = excavation length in feet
  • Width = excavation width in feet
  • Average depth = excavation depth in feet
  • Swell % = expected increase in volume after excavation

Assumptions: The footprint is treated as a rectangular prism. Slopes, benches, over-excavation, structures, and irregular grade surfaces are not included unless reflected in the dimensions you enter.

What the result means

Use the result as a planning estimate tied to the inputs and assumptions shown above. Compare it with project-specific records, drawings, specifications, and field conditions before making commitments.

Inputs and production factors can vary by material, equipment, crew, measurement basis, and site conditions; update the assumptions when better project data is available.

Given:

  • Length = 60 ft
  • Width = 20 ft
  • Average depth = 6 ft
  • Swell allowance = 25%

Calculation:
Bank volume = 60 × 20 × 6 = 7,200 cu ft
Bank cubic yards = 7,200 ÷ 27 = 266.67 cu yd
Loose volume = 266.67 × 1.25 = 333.33 cu yd
Swell volume = 333.33 − 266.67 = 66.67 cu yd

Result: 266.67 bank cu yd

The excavation contains about 266.67 cubic yards in place. At the entered swell factor, handling or hauling may involve about 333.33 loose cubic yards.

What is bank volume?

Bank volume is the quantity of material measured in its undisturbed in-place condition before excavation.

How do I choose a swell percentage?

Use geotechnical information, project specifications, historical field data, or material-specific guidance appropriate to the soil or rock being excavated.

Does this include sloped excavation sides?

Not automatically. If side slopes materially increase volume, model the excavation in sections or use geometry that includes those slopes.

Can I use average depth on a sloping site?

Yes for a preliminary estimate when the average is well supported. For large grade changes, dividing the site into smaller areas generally produces a better quantity.

Is loose volume the same as trucked volume?

It is a planning estimate. Actual trucked volume can differ because of loading practice, compaction in the truck, moisture, segregation, and measurement method.